The long-term goal of this research is to expand our understanding of the neuroendocrine mechanisms underlying social interactions. Parental interactions with young are particularly important components of the social behavior repertoire because they are critical for survival. However, the neural and hormonal mechanisms underlying these interactions have not been adequately described and the question of whether the neural circuitry involved in parenting is common to other social behaviors remains to be resolved. The proposed studies explore the neural mechanisms responsible for the integrative actions of prolactin (PRL) in coordinating the diverse behavioral and neuroendocrine changes that are necessary for successful parental care. The ring dove (Streptopelia risoria) is chosen as the model species for investigation because it has an unusually rich repertoire of PRL-dependent behavioral and physiological changes that support parenting. The project has four specific aims: 1) to use immunocytochemical mapping of immediate early gene products to determine if PRL, social cues, and experiential factors influence activity in neuronal circuits that underlie parental motivation and parental behavior expression; 2) to determine if PRL signaling in the brain is modulated by previous parenting experience and during physiological states associated with parenting (using real time PCR, in situ hybridization, and immunocytochemistry to measure PRL receptor expression and nuclear translocation of PRL-sensitive signaling molecules); 3) to explore the role of gonadotropin releasing hormone (GnRH) and gonadotropin inhibiting hormone (GnlH) in mediating PRL's suppressive action on gonadal activity, which may be necessary in order for other PRL-induced changes in parental responsiveness to be displayed (using real time PCR, in situ hybridization, and immunocytochemistry to measure expression in specific brain regions); 4) to determine the functional importance of PRL signaling in the brain in promoting parental behavior and gonadal axis suppression (using antisense oligonucleotide technology to knock down PRL receptor expression in dove brain). These studies will expand our understanding of neural mechanisms underlying sociality and could lead to better diagnosis and treatment of individuals at risk for social adjustment disorders. They may also shed light on the causes of infertility in nursing women with elevated PRL secretion and in men and women with PRL-secreting pituitary tumors. [unreadable] [unreadable] [unreadable]